package com.zhjedu.util;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

/**
 * <DL>
 * <DT><B>标题. </B></DT>
 * <p>
 * <DD>详细介绍</DD>
 * </DL>
 * <p>
 * 
 * <DL>
 * <DT><B>使用范例 </B></DT>
 * <p>
 * <DD>使用范例说明</DD>
 * </DL>
 * <p>
 * 
 * @author w-jialin
 * @author wzsr
 */
public class SetCharacterEncodingFilter implements Filter {
    protected String encoding = null;

    protected FilterConfig filterConfig = null;

    protected boolean ignore = true;

    public void destroy() {

        this.encoding = null;
        this.filterConfig = null;

    }

    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        // Conditionally select and set the character encoding to be used
        if (ignore || (request.getCharacterEncoding() == null)) {
            String encoding = selectEncoding(request);
            if (encoding != null)
                request.setCharacterEncoding(encoding);
        }
        
        // Pass control on to the next filter
        chain.doFilter(request, response);

    }

    public void init(FilterConfig filterConfig) throws ServletException {

        this.filterConfig = filterConfig;
        this.encoding = filterConfig.getInitParameter("encoding");
        String value = filterConfig.getInitParameter("ignore");
        if (value == null)
            this.ignore = true;
        else if (value.equalsIgnoreCase("true"))
            this.ignore = true;
        else if (value.equalsIgnoreCase("yes"))
            this.ignore = true;
        else
            this.ignore = false;

    }

    protected String selectEncoding(ServletRequest request) {

        return (this.encoding);

    }


}
